Portable folding boom



Aug. 31, 1954 N. F. HuRsT PORTABLE FOLDING BOOM 2 Sheets-Sheet l Filed Aug. 28. 1953 INVENTOR. Norman I''Hurs'f' Aug.V 31, 1954 N, F, HURs-r 2,687,811

PORTABLE FOLDING BOOM Filed Aug. 28. 1.953 2 Sheets-Sheet 2 Fi T `5 INVENTOR.

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Patented Aug'.` 31, 1954 e PoR'rAsLE FOLDING BooM Norman F. Hurst, Aurora, Oreg., assigner to Ralph M. Osvold and Norman F. Hurst, a copartnership, doing business as Hurst Truck Utilities, Portland, Oreg.

Application August 28, 1953, Serial No. 377,101

This invention relates to booms for lifting loads and, more particularly, toportable boomsof a type which may be collapsed and stowed on a truck body when not in use. a

There have been many prior art suggestions for the construction of portable booms. One type with which I am familiar has two side legs which are raised and lowered by hydraulic cylinders. Another type hastwo side legs and a hydrauli-` cally operated middle or brace leg which positions the two side legs. In stowedposition the legs of either type of boom are folded or telescoped. When the boom has been raised and prior to being. put in operative use, the upper portions of the legs must usually be securely fastened to the lower portions by some locking means such as pins or latches. Such arrangements are cumbersome and necessitate an extra manual operation on the part of someone, which is dangerous in that the boom may collapse if it has not been securely fastened, or if one is working around overhead high tension wires, a person setting a latch is in danger of being electrocuted.` There are also certain confining limitations on the type of work and locations in which the booms heretofore known can successfully operate. Additionally, with three-legged booms the middle leg, of necessity, is positioned in the center of the truck body where it takes up space which could well be utilized for the stowage of materials or tools. While my invention is generally applicable to all vehicles, it has been found to be particularly suited for public utility service trucksof the type used for setting and removing poles carrying overheadlines, transformers, and other equipment.

According to my invention, the folding boom comprises a pair of legswhich are joined at their apex and in carrying position normally lie flat on the top of the truck with their apex over the cab of the truck. At their free ends, the legs are pivotally mounted in vertically slotted guideways at the rear ofthe truck. Connected to each leg near the apex is a piston from an hydraulic cylinder which is pivotally connected to the body of the truck and is free to follow the movement of the legs. There are mounted on the truck nearthe slotted guideways a pair of vertical cylinders whose pistons are connected to the pivoted ends of the legs. The first-mentioned pair of hydraulic cylinders control for the most part `the erection and lowerings of the legs as they are moved in an arc from an at rest position to operative positions atdifferent angles to the body of the truck. The second pair of cylinders provide cushioned supports for the legs in the opera-.

5 Claims. (Cl. 212-8) e tive positions, and can also be utilized to vary the length of the legs.

It will be appreciated that some of the advantages and features afforded by my improved boom are simplification of construction; a live boom from the time it is first put into operation. By flive is meant a boom whose position. and length can be independently controlled while carrying a load. The inside body area of the truck is free for a stowage of tools and materials. If it is desired to drop a load directly into the truck, there is no boom operating gear which will interfere. Loads can be carried by the boom on either side of its vertical position which permits the boom being used to load and unload the truck itself. One man can operate the boom conveniently because it is unnecessary to fasten and uniasten folding leg members when they are put into and out of operative position. The cushioning action of the vertical hydraulic cylinders insures better and safer operation of the boom and may be operated simultaneously or independently of the other pair` of cylinders to vary the length of the boom and provide an added area in which the boom has working positions. The combination of the two sets of cylinders generally gives much greater fiexibility in the use of the boom and permits `it to be adapted to varying conditions and eliminates to a great extent the necessity of having to move the truck for minor position adjustments of the boom.

On all other booms with which I am familiar, it is not possible to vary the height of the boom without moving it through an arc, and the only way in which the vertical position of the load being carried by the boom may be Varied is by means of operating the winch to move the hook carrying the load. Frequently, it is desirable to be able to change the height at which a load is being carried without moving the boom in an arc or dropping the load and picking it up at another point. For example, when setting a telephone pole in a hole in the ground, it often happens that after the boom has been lifted to its position of maximum elevation, the pole does not clear the ground, permitting it to be set in the hole. With pre-existing booms, it is necessary to lower the pole to the ground and set the hook. at a lower position on the pole. With my improved boom, this would not be necessary because after the boom had reached an upright position, the vertical cylinders can be operated to raise the boom and pole an extra amount sufficient, in the usual situation, to provide the necessary clearance so. that the pole can be set in the hole. i The ability which, of course, presents a continual danger of fouling the overhead wires.

The advantages and features of the invention will become more apparent from the following detailed description taken in conjunction with the drawings, in which:

Fig. 1 is a side elevation of a truck with the im..

-proved boom thereon;

Fig. 2 is a rear end View of the truck and boom;

Fig. 3 is an enlarged section on lines 3-3 of Fig. 2;

Fig. i is an enlarged section on lines 4 4 of Fig. 2; and

Fig. 5 is a side elevation of a truck with the boom in two ofits operative positions.

Referring to the drawings, the chassis of truck IG has a body generally indicated at il, having two sides I2 and i3. In between sides I2 and i3, there is a vacant space Iii which may be conveniently used -for the storage of tools or other material which it is desired to carry on the truck. rI'he top of the truck between sides I2 and I3 may be open, closed, or, as is more common, sliding, so that it may be converted from open to closed. The boom comprises two rigid upwardly converging legs Iii, I6 which are joined to one another at an apex where there is provided a sheave Il. A cable It having a hook IQ at one end runs through sheave ll and, by means of a suitable wnch 2G on the truck, the cable may be operated to lift and lower loads fastened to the hook.

A pair of horizontal hydraulic cylinders 2l, 22 are pivotally fastened at 23, 24 to supporting members I2 projecting slightly above the tops of the sides of the truck. Pistons 25, 26 in cylinders 2l, 22 have their free ends fastened by brackets 2l, 28 to each of legs I5, I6 at points nearer the apex of the legs than their rear ends. The rear ends of legs i5, I6 are flattened (Fig. 3) and welded to round bars 29, 3l). Bound bars 29, 3&3 extend into vertical slotted guideways SI, 32 which are formed between upstanding I-beams 33 and box beams 35i. Washers 35, 36 surrounding bar 363 are provided on either side of the beams. Loosely ntting collars 3l surround the other ends of bars 29, Sli and are held thereon by means of washers 36 and nuts 3,9.

Collars 3l are fastened to the free ends of pistons de, 4S which operate in vertical hydraulic cylinders lll, di?. Cylinders 4l, 48 are mounted at the rear of the truck on either side vand are in cooperative relation with slotted guideways 3i, 32.

When the boom is in its at rest, or stowed,

Y position, as shown in solid lines Figs. 1 and 2,

number of ways familiar to those skilled in the art.

As best seen from Figs. 1 and 5, one of the features of the boom is that the combination of the vertical cylinders whose pistons are pivotally connected to the heels or bases of legs I5, l@ and the other pair of cylinders which move the legs through an arc permit the boom to be moved into `any number of different vertical and horizontal positions within area X. In this manner, by means simply of moving the boom itself rather than the truck or hook, the boom while carryingT a load can adapt itself to any number of situations. In this sense, the boom is truely a live boom throughout its range of operative positions.

Fig. 5 shows the boom in its two positions of maximum elevation. In the position shown in solid lines, the pistons 45, l are fully extended and pistons 25, 26 partially extended. In the position shown in dotted lines, the boom has been vertically lowered by completely Iretracting pistons d5, lo and retracting pistons 25, 255 a little from the position shown in solid lines.

The boom is operated in the following manner: Commencing with the hoorn in stowed, or at rest, position on top of the truck, cylinders I, 22 are operated and as their pistons 2d, are extended, legs IE5, I are moved upwardly, in the direction indicated by the arrows in Fig. l, in an arc as bars 2Q, 323 pivot in the guideways. If it is desired to move the boom into its position of maximum effective reach, pistons 26 will be compietely extended to move the boom substantially through into horizontal position shown in dotted lines Fig. l, and 'vertical pistons L15, ed will be co-mpleteiy retracted into cylinders to provide suicient triangulation so that a load may be hoisted. In this position the boom can be moved into otherwise inaccessible positions, such as under low hanging impediments, trees, buildings, etc. By retracting pistons 25, 2li, the load which has been secured to hoolr'l may be lifted and ultimately swung into space tl in the truck, if desired.

As shown by area X, the boom has a wide range of operative positions into which it can be moved. The controls for the hydraulic cylinders may be conveniently located in the cab of the truck so that control of the boom can be a one man operation from the raising of the boom into operative position to stowing it back on top ci the truck.

While a preferred embodiment of the invention has been here disclosed, it is to be understood that variations and changes in the apparatus will be suggested to those skilled in the art, and it is intended to encompass such variations and changes the present invention which is to be limited only as defined in the appended claims.

I claim:

1. A portable folding boom for a vehicle or the like which :is adapted to be moved into and out of operative position by one man comprising, a vehicle chassis, a supporting frame on the chassis, a pair of legs connected to one another at one end and separated from each other at the other end, a rst pair of hydraulic cylinders pivotally supported .at one end on said supporting frame, a piston extending from each of said cylinders and fastened to a corresponding leg, vertical guideways for slidably supporting said separated ends of the legs, bar means extending from each of said ends of the legs into the guideways, a second pairY of hydraulic cylinders vertically mounted in cooperative relation with said guideways, and a piston extending from each of said last-mentioned cylinders connected to said bar means.

' 2. A portable folding boom for a vehicle having a body with sides and a top, said boom having a normal at rest horizontal position in which it lies substantially at on top of the vehicle body and operative positions in which it is raised at different angles to the body comprising a supporting frame, a pair of upwardly converging legs `joined together 'at one end in an apex, a first pair of hydraulic cylinders having one end pivotally mounted on the frame and at the other end connected to each of the legs near the apex, said first pair of cylinders being substantially horizontal in the at rest position of the legs, vertical guide means on either side of the vehicle body, the other end of said legs mounted in saiolV guides, a second pair of vertically mounted hydraulic cylinders cooperating with the guides and connected at one end to the legs, and means for controlling the operation of said hydraulic cylinders. l

3. A portable folding boom for a truck having a body with closed sides and sliding top, said boom having a normal at rest horizontal position in which it liessubstantially flat on the top of the truck body and operative positions in which it is raised at different angles to the body, comprising a supporting frame, a pair of upwardly converging legs joined together at an apex and having free ends separated from one another, a first pair of hydraulic cylinders having one end pivotally mounted near the top of the frame on either side of the truck body, a piston extending from the other end of each of the cylinders connected to each'of the legs near the apex, said first pair of cylinders being substantially horizontal in the at rest position of the legs, vertical slotted guides at the rear of the truck body on either side thereof, said free ends of the legs mounted in said guides,

a second pair of hydraulic cylinders vertically mounted at the rear of the truck body in cooperative relation with said guides, a piston extending from each of said second cylinders, a pivot connection between each of said free ends of the legs of the boom and the pistons slidably mounted in said guides, and means for controlling the operation of said hydraulic cylinders.

4. A portable folding boom for a vehicle having a supporting framework, said boom having a transport position in which it is approximately horizontal, and an operative position in which it is raised at different angles to the framework; said boom comprising aA pair of upwardly converging legs joined together at one end in an apex, hydraulic cylinder means pivotally mounted on the framework and connected to said legs for moving the legs through an arc, substantially vertical guide means, said guide means including a pair of spaced vertical members providing parallel slideways, slide means shiftably mounted in each slideway for operative connection to the other ends of the legs whereby` said legs are slidably supported for substantially vertical movement in said guide means, and power-driven extensible means operatively associated with said legs for vertically raising and lowering the legs in said guide means.

5. The apparatus according to claim 4, and in which said extensible means is` hydraulic cylinder means.

References Cited in the lle of this patent UNITED STATES PATENTS Number Name Date 1,817,392 Ohliger Aug. 4, 1931 2,557,466 Richards et al June 19, 1951 2,601,927 Frenzel July 1, 1952 2,636,717 Powers Apr. 28, 1953 2,645,360 Raymond July ,14, 1953 

